Cotus leucanthus is rarely found in cultivation. It is from the eastern lowland jungles of Colombia and Ecuador. It grows to 8-10 feet tall with unusual triangular shaped appendaged bracts and pure white flowers with just a touch of pale yellow on the lebellum.
I have not grown it for very long and do not have any experience with hardiness, but guessing it would only be outdoors hardy in USDA zone 10 or warmer. I have always seen it growing (in nature) in sunny areas and close to streams so I would recommend moist soil and full sun for this plant in cultivation.